It is commonly known that a liquid crystal panel, an organic EL panel and similar display panels exhibit unevenness in display, such as luminance unevenness and color unevenness, due to manufacturing variations such as unevenness in cell gaps and unevenness in the brightness of a backlight. When each pixel in a display panel has RGB display elements, unevenness in luminance occurs if a relative relationship among R, G and B in each individual pixel in terms of brightness does not vary but the absolute brightness varies between neighboring pixels, and unevenness in color occurs if a relative relationship among R, G and B in each individual pixel in terms of brightness varies between neighboring pixels.
There are techniques to improve the image quality of a display panel by reducing such unevenness in display. One example is an image correction data generation system described in PTL 1. This system displays a gray image across the entire display panel, calculates the luminance distribution of the gray image by capturing the gray image with a camera, and generates correction data based on the luminance distribution. The generated correction data is stored in a correction circuit provided in the display panel. When an image signal is input to the display panel, the correction circuit corrects the input signal based on the correction data. As a result, unevenness in display is reduced.